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  4. why QProcess not show output of ls /dev/sd* command ?
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why QProcess not show output of ls /dev/sd* command ?

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  • Q Qt embedded developer

    @jsulm said in why QProcess not show output of ls /dev/sd* command ?:

    shell is resolving *

    so what i need to do to execute it ?

    i think its not relative path this is absolute path. if not then can you let me know how i can get absolute path ?

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by
    #6

    @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

    can you let me know how i can get absolute path ?

    Execute the bellow command:
    which ls

    https://forum.qt.io/topic/113070/qt-code-of-conduct

    JonBJ 1 Reply Last reply
    1
    • jsulmJ jsulm

      @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

      can you let me know how i can get absolute path ?

      Execute the bellow command:
      which ls

      JonBJ Offline
      JonBJ Offline
      JonB
      wrote on last edited by JonB
      #7

      @jsulm said in why QProcess not show output of ls /dev/sd* command ?:

      which ls

      Observation: if which finds ls then there is no need to use a full path to it. And if it's not on your path which won't find it! :)

      1 Reply Last reply
      1
      • jsulmJ jsulm

        @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

        i think its not relative path this is absolute path

        How is ls an absolute path?!
        On my Ubuntu machine the absolute path to ls is /usr/bin/ls

        I'm wondering why you need QProcess for such a task at all? You can simply use https://doc.qt.io/qt-6/qdir.html

        Q Offline
        Q Offline
        Qt embedded developer
        wrote on last edited by
        #8

        @jsulm means i just need to check there is file name start with sd is there on not int /dev directory

        jsulmJ 1 Reply Last reply
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        • JonBJ JonB

          @Qt-embedded-developer
          Because your /dev/sd* has a * wildcard in it. ls (or any other Linux command) does not expand wildcards. Only a shell expands wildcards! If you want to do it this way you will need:

           Command = "/bin/sh";
          
          args << "-c" << "ls /dev/sd*";
          

          Note that running a command to expand a filepath like this is not "efficient". You could do the work from, say, Qt QDir on /dev and look through the child filenames yourself to see which start with sd. Or QFileInfoList QDir::entryInfoList(const QStringList &nameFilters, QDir::Filters filters = NoFilter, QDir::SortFlags sort = NoSort) const could be used to do the wildcard matching. This would also be a lot cleaner than your code trying to parse ls's output.

          Q Offline
          Q Offline
          Qt embedded developer
          wrote on last edited by
          #9

          @JonB said in why QProcess not show output of ls /dev/sd* command ?:

          QFileInfoList QDir::entryInfoList(const QStringList &nameFilters, QDir::Filters filters = NoFilter, QDir::SortFlags sort = NoSort) const

          as per my case what i need to write in above ?

          jsulmJ 1 Reply Last reply
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          • Q Qt embedded developer

            @jsulm means i just need to check there is file name start with sd is there on not int /dev directory

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #10

            @Qt-embedded-developer Yes, get entries in /dev folder using QDir::entryInfoList and filter all entries starting with sd (you can pass file name filter directly to QDir::entryInfoList).

            https://forum.qt.io/topic/113070/qt-code-of-conduct

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            • Q Qt embedded developer

              @JonB said in why QProcess not show output of ls /dev/sd* command ?:

              QFileInfoList QDir::entryInfoList(const QStringList &nameFilters, QDir::Filters filters = NoFilter, QDir::SortFlags sort = NoSort) const

              as per my case what i need to write in above ?

              jsulmJ Offline
              jsulmJ Offline
              jsulm
              Lifetime Qt Champion
              wrote on last edited by
              #11

              @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

              as per my case what i need to write in above ?

              What exactly is not clear?

              https://forum.qt.io/topic/113070/qt-code-of-conduct

              Q 1 Reply Last reply
              1
              • jsulmJ jsulm

                @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

                as per my case what i need to write in above ?

                What exactly is not clear?

                Q Offline
                Q Offline
                Qt embedded developer
                wrote on last edited by Qt embedded developer
                #12

                @jsulm sorry its clear. i have to try. but if possible can you give example so it can help better.

                Christian EhrlicherC 1 Reply Last reply
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                • Q Qt embedded developer

                  @jsulm sorry its clear. i have to try. but if possible can you give example so it can help better.

                  Christian EhrlicherC Online
                  Christian EhrlicherC Online
                  Christian Ehrlicher
                  Lifetime Qt Champion
                  wrote on last edited by
                  #13

                  @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

                  but if possible can you give example so it can help better.

                  Maybe reading the answers would help - it was already given...

                  Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                  Visit the Qt Academy at https://academy.qt.io/catalog

                  Q 1 Reply Last reply
                  0
                  • Christian EhrlicherC Christian Ehrlicher

                    @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

                    but if possible can you give example so it can help better.

                    Maybe reading the answers would help - it was already given...

                    Q Offline
                    Q Offline
                    Qt embedded developer
                    wrote on last edited by Qt embedded developer
                    #14

                    @Christian-Ehrlicher i have tried like below but i am getting empty list from fileinfolist

                    QString myPath="/dev";
                            QDir dir;
                            dir.setPath(myPath);
                            QStringList filters;
                            filters<<"sd";
                            dir.setFilter( QDir::AllEntries | QDir::System);
                            dir.setNameFilters(filters);
                            dir.setSorting(QDir::Name );
                            QFileInfoList list = dir.entryInfoList();
                    
                    

                    why my list is not giving file name what is expected ?

                    JonBJ 1 Reply Last reply
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                    • Christian EhrlicherC Online
                      Christian EhrlicherC Online
                      Christian Ehrlicher
                      Lifetime Qt Champion
                      wrote on last edited by
                      #15

                      Because there is no /dev/sd in your directory. Please read the documentation...

                      Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                      Visit the Qt Academy at https://academy.qt.io/catalog

                      Q 1 Reply Last reply
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                      • Christian EhrlicherC Christian Ehrlicher

                        Because there is no /dev/sd in your directory. Please read the documentation...

                        Q Offline
                        Q Offline
                        Qt embedded developer
                        wrote on last edited by
                        #16

                        @Christian-Ehrlicher actually above code i written to find name that start with sd .

                        Christian EhrlicherC 1 Reply Last reply
                        0
                        • Q Qt embedded developer

                          @Christian-Ehrlicher actually above code i written to find name that start with sd .

                          Christian EhrlicherC Online
                          Christian EhrlicherC Online
                          Christian Ehrlicher
                          Lifetime Qt Champion
                          wrote on last edited by Christian Ehrlicher
                          #17

                          @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

                          actually above code i written to find name that start with sd .

                          No, RTFM!

                          Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                          Visit the Qt Academy at https://academy.qt.io/catalog

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                          • Q Qt embedded developer

                            @Christian-Ehrlicher i have tried like below but i am getting empty list from fileinfolist

                            QString myPath="/dev";
                                    QDir dir;
                                    dir.setPath(myPath);
                                    QStringList filters;
                                    filters<<"sd";
                                    dir.setFilter( QDir::AllEntries | QDir::System);
                                    dir.setNameFilters(filters);
                                    dir.setSorting(QDir::Name );
                                    QFileInfoList list = dir.entryInfoList();
                            
                            

                            why my list is not giving file name what is expected ?

                            JonBJ Offline
                            JonBJ Offline
                            JonB
                            wrote on last edited by
                            #18

                            @Qt-embedded-developer said in why QProcess not show output of ls /dev/sd* command ?:

                            filters<<"sd";

                            void QDir::setNameFilters(const QStringList &nameFilters)

                            Each name filter is a wildcard (globbing) filter that understands * and ? wildcards. See QRegularExpression::fromWildcard().

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